Car accessory that's fixed on for us (7)
I believe the answer is:
sunroof
'car accessory' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'fixed on for us' is the wordplay.
'fixed' is an anagram indicator.
'on'+'for'+'us'='onforus'
'onforus' anagrammed gives 'SUNROOF'.
'that's' is the link.
Can you help me to learn more?
(Other definitions for sunroof that I've seen before include "Openable panel in top of car" , "Car top ventilator" , "Car feature" , "Retractable panel in car" , "Opening above a driver's head" .)